Around Sound App: Once you've launched this free app, you'll need to give a definite trigger level so that your music stops. It's better if you can set it above your normal ambient noise level so that the music does not pause with sounds like a typing on a keyboard or traffic. In this version, the noises might either pause your music or lower the volume, on the preferences you've set. It feeds the outside sound to your headset so you can hear what is going on.

Around Sound App Pro costs $2 where you get the option of Street Mode that lets you to hear to sounds higher than the set trigger level even as you continue to listen to music, mixing your outside and inside sounds. It would be helpful when you are walking on a busy noise with your music on and you do not want the music to stop at any sudden noise but do want to hear-in on what is happening.

Apps like these will need headphones with a built-in mic for better results. Though there are issues like a delay of 500 ms persists, it might be fixed by Jelly Bean.

Hear Voice app: This app costs $1.50, but even that's too much, since all you're paying for is "add a background of constant buzzing and static to your music."

To top it off, you can hear very little of environmental sounds registered in the app as the static emanating from the appis that loud. If you increase the volume of the app though you can listen to the outside noise, it also raises the static volume. This is definitely not as good as Around Sound App.